02281naa a2200265 a 450000100080000000500110000800800410001910000190006024500890007926000090016850001330017752013910031065000190170165000160172065000160173665300190175265300170177165300250178865300270181365300200184070000180186070000220187870000220190077300930192220595102017-05-24       2016    bl uuuu     u00u1 u    #d1 aPADILHA, A. H.  aReability of breeding values between random regression and 305-day lactation models.  c2016  aTítulo em português: Confiabilidade de valores genéticos entre modelos de regressão aleatória e de lactação aos 305 dias.  aThe objective of this work was to verify the gain in reliability of estimated breeding values (EBVs), when random regression models are applied instead of conventional 305-day lactation models, using fat and protein yield records of Brazilian Holstein cattle for future genetic evaluations. Data set contained 262,426 test-day fat and protein yield records, and 30,228 fat and protein lactation records at 305 days from first lactation. Single trait random regression models using Legendre polynomials and single trait lactation models were applied. Heritability for 305-day yield from lactation models was 0.24 (fat) and 0.17 (protein), and from random regression models was 0.20 (fat) and 0.21 (protein). Spearman correlations of EBVs, between lactation models and random regression models, for 305-day yield, ranged from 0.86 to 0.97 and 0.86 to 0.98 (bulls), and from 0.80 to 0.89 and 0.81 to 0.86 (cows), for fat and protein, respectively. Average increase in reliability of EBVs for 305-day yield of bulls ranged from 2 to 16% (fat) and from 4 to 26% (protein), and average reliability of cows ranged from 24 to 38% (fat and protein), which is higher than in the lactation models. Random regression models using Legendre polynomials will improve genetic evaluations of Brazilian Holstein cattle due to the reliability increase of EBVs, in comparison with 305-day lactation models.  aBreeding value  aCorrelation  aReliability  aCinfiabilidade  aCorrelação  aLegendre polynomials  aPolinômio de Legendre  aValor genético1 aCOBUCI, J. A.1 aDALTRO, D. dos S.1 aBRACCINI NETO, J.  tPesquisa Agropecuária Brasileira, Brasília, DFgv. 51, n. 11, p. 1848-1856, nov. 2016.